const int lampu1Pin = 2;
const int lampu2Pin = 3;
const int lampu3Pin = 4;

void setup() {
 pinMode(lampu1Pin, OUTPUT);
  pinMode(lampu2Pin, OUTPUT);
  pinMode(lampu3Pin, OUTPUT);

}

void loop() {

  digitalWrite(lampu1Pin, HIGH);
  delay(1000); 

  digitalWrite(lampu1Pin, LOW);
  digitalWrite(lampu2Pin, HIGH);
  delay(1000); 

  digitalWrite(lampu2Pin, LOW);
  digitalWrite(lampu3Pin, HIGH);
  delay(1000); 

 
  digitalWrite(lampu3Pin, LOW);
  delay(1000); 

}